Heat dissipating device for transmission line, transmission line with heat dissipating device, and method for fitting heat dissipating device to transmission line

ABSTRACT

The present invention realizes an increase of the capacity of a power transmission wire without replacing an already strung aerial power transmission wire. For this purpose, a braided heat conducting wire heat dissipating belt ( 1 ) treated to blacken its surface so that a surface heat dissipation rate becomes 0.7 or more or a surface-blackened heat dissipating spiral rod is wound around an outer circumference of an already strung aerial line ( 2 ) or jumper ( 8 ) so as to increase the heat dissipation effect of the surface of the aerial line ( 2 ). Heat dissipation enables the capacity of a permissible power supply of the already existing aerial line ( 2 ) to be increased. Further, the braided heat conducting wire heat dissipating belt ( 1 ) shares the transmission function and lowers the wind noise.

This application is the U.S. National Phase under 35 U.S.C. §371 ofInternational Application PCT/JP99/01257, filed Mar. 15, 1999, whichclaims priority based on JP 10-82498, filed Mar. 14, 1998.

TECHNICAL FIELD

The present invention relates to a power transmission wire heatdissipator wound around an aerial power transmission wire or other powertransmission wire for dissipating the heat of the power transmissionwire, a power transmission wire (line) equipped with a heat dissipator,and a method for attaching a heat dissipator on a power transmissionwire.

BACKGROUND ART

It is desired to increase the power transmission capacity of an aerialline (wire).

When the power transmission capacity is increased, the current flowingthrough the line becomes heated. Therefore, a permissible upper limit isset on the current flowing through the aerial line.

Therefore, the general method of increasing the transmission capacity ofan aerial line is use of an aerial line having a larger sectional area.

In the case of an already strung aerial line, the transmission capacityis increased by replacing it with another line having a larger sectionalarea.

However, a line having a large sectional area becomes heavier in theweight of the line per unit length, so the amount of sagging (sag orslack) becomes larger due to the line's own weight. If the sag becomeslarger, the distance to the ground etc. becomes shorter, so the towersmust be made higher and must be made stronger in structure in somecases. Such replacement of towers is difficult in view of on-goingoperations, work, and costs in many cases. When replacing a tower withone having a higher height and greater strength or fabricating a higherand stronger tower in advance so that a power transmission wire having alarger sectional area will be able to be laid in the future, theproblems of a rise of the manufacturing cost of the tower and a rise ofthe transmission cost are encountered. Also, when the transmissioncapacity is further increased, the above problem of an increase in theamount of heat generated in the aerial line is still encountered.

As one method of overcoming the problem of the increase of the sag, usehas been made of aerial lines made of twisted steel-reinforced aluminumconductors (ACSR)—conductors reinforced by Invar steel wires having asmall coefficient of linear expansion and known for low sag. When newlystringing an aerial line made of Invar-reinforced aluminum conductors,the problem of the height of the tower can be overcome since the sag ofthe ACSR aerial line is small. When trying to increase the transmissioncapacity of an aerial line made of Invar-reinforced aluminum conductors,however, the number of aluminum conductors has to be increased or thesectional area of the aluminum conductors has to be enlarged. The weightof the aerial line is therefore increased so an excessive load isapplied to the tower, and the price of the aerial line becomesremarkably high. Accordingly, the above problem cannot be overcome justby using ACSR for the aerial line.

Further, as one method of overcoming the problem of the large heatgeneration explained above, use has been made of aerial lines made ofthermo-resistant conductors able to withstand high temperature use. Forexample, if an aerial line made of steel-reinforced ultrathermo-resistant aluminum alloy conductors (UTACSR) is used, usage at ahigh temperature of 200° C. or more is possible. Heating, however,causes the aerial line to elongate. In particular, the increase of thesag of the aerial line at the time of a high temperature cannot beignored. Therefore, the problem of an increase of the sag is stillencountered if just using UTACSR for the aerial line.

Japanese Unexamined Patent Publication (Kokai) No. 64-81110 and JapaneseUnexamined Patent Publication (Kokai) No. 64-81111 disclose a techniqueof covering the outer circumference of the aerial line with a mesh beltso as to prevent the accumulation of snow from causing a tubular mass ofsnow (snow tubes) from depositing on the outer circumference of theaerial line, increasing the weight of the aerial line, causing sag andin turn breaking the aerial line. However, the technique disclosed inJapanese Unexamined Patent Publication (Kokai) No. 64-81110 and JapaneseUnexamined Patent Publication (Kokai) No. 64-81111 is a techniqueconsidering only the prevention of tubular accumulation of snow, and nota technique for increasing the transmission capacity of the aerial line.Particularly, Japanese Unexamined Patent Publication (Kokai) No.64-81110 and Japanese Unexamined Patent Publication (Kokai) No. 64-81111do not disclose a technique for increasing the transmission capacity ofan aerial line by improving the heat dissipation characteristic of theaerial line.

Japanese Unexamined Patent Publication (Kokai) No. 48-72688 (JapaneseUnexamined Patent Publication (Kokoku) No. 52-4357) discloses atechnique of preventing galloping, which frequently occurs when there isuniform accumulation of ice and snow along a longitudinal direction ofthe windward side of an aerial line by winding an S-twist and Z-twisthelical shaped body having a predetermined length around the outercircumference of the aerial line so that the S-twist and the Z-twist arearranged repeatedly or at random. However, Japanese Unexamined PatentPublication (Kokai) 48-72688 also does not disclose a technique ofincreasing the transmission capacity of an aerial line by improving theheat dissipation characteristic of the aerial line.

Japanese Unexamined Patent Publication (Kokai) No. 49-101876 (JapaneseExamined Patent Publication (Kokai) No. 53-14146) discloses a techniqueof reducing the noise due to wind pressure on the aerial line by settingthe outer diameter of the strands and the outer diameter of the line ofa low noise line comprised of strands wound helically or cross-wise andsetting the winding pitch to within a predetermined range. However,Japanese Unexamined Patent Publication (Kokai) No. 49-101876 also doesnot disclose a technique of increasing the transmission capacity of anaerial line by improving the heat dissipation characteristic of theaerial line.

Japanese Unexamined Patent Publication (Kokai) No. 57-98907 (JapaneseExamined Patent Publication (Kokoku) No. 58-38884) discloses an aerialline reducing the corona noise of the aerial line by providing a lownoise line comprised of a line around the outer circumference of whichstrands are wound where a plurality of unit strands formed with minuteunevenness on the surface of the wound strands are arranged in closecontact. However, Japanese Unexamined Patent Publication (Kokai) No.57-98907 also does not disclose a technique of increasing thetransmission capacity of an aerial line by improving the heatdissipation characteristic of the aerial line.

Japanese Unexamined Patent Publication (Kokai) No. 6-302223 disclosesreducing the noise due to wind pressure and, further, reducing an ANlevel by providing a low noise line in which part of the outermost layerof the aerial line is made to project out. However, Japanese UnexaminedPatent Publication (Kokai) No. 6-302223 also does not disclose atechnique of increasing the transmission capacity of an aerial line byimproving the heat dissipation characteristic of the aerial line.

DISCLOSURE OF THE INVENTION

An object of the present invention is to provide a heat dissipator to beattached on a power transmission wire in order to enable an increase ofthe transmission capacity without an increase of the sectional area ofthe power transmission wire itself.

Another object of the present invention is to provide a heat dissipatorto be attached on a power transmission wire in order to enable anincrease of the transmission capacity without an increase of thesectional area of the power transmission wire itself and, further, toenable prevention of accumulation of snow, reduction of noise due towind pressure, reduction of the corona noise, and prevention ofgalloping.

Still another object of the present invention is to provide a powertransmission wire on which the heat dissipator is attached in order toenable an increase of the transmission capacity without an increase ofthe sectional area of the power transmission wire itself.

Still another object of the present invention is to provide a powertransmission wire on which a heat dissipator is attached in order toenable an increase of the transmission capacity without an increase ofthe sectional area of the power transmission wire itself and, further,to enable prevention of accumulation of snow, reduction of noise due towind pressure, reduction of the corona noise, and prevention ofgalloping.

Still another object of the present invention is to provide a method ofattaching such a heat dissipator on a power transmission wire.

According to a first aspect of the present invention, there is provideda heat dissipator for a power transmission wire comprised of aconductive heat dissipation member having conductivity and having asurface heat dissipation rate of 0.7 or more spirally wound around theouter circumferential surface of the power transmission wire at apredetermined winding pitch in close contact thereto.

Preferably, the conductive heat dissipation member is treated to blackenits surface and delustered.

Further preferably, the surface of the conductive heat dissipationmember is treated to make it hydrophilic.

Also, preferably, the conductive heat dissipation member has a surfacewhich is artificially or naturally aged in advance.

Preferably, the conductive heat dissipation member is produced byaluminum or an aluminum alloy.

According to the first aspect, the conductive heat dissipation member ofthe heat dissipator for a power transmission wire has a braided heatconducting wire heat dissipating belt comprised of heat conducting metalstrands braided in the form of a mesh belt, the braided heat conductingwire heat dissipating belt being spirally wound around the outercircumferential surface of the power transmission wire at apredetermined winding pitch.

In the first aspect, preferably, the braided heat conducting wire heatdissipating belt has a winding pitch giving a center angle θ of thewinding width on the circumference of the cross-section of the powertransmission wire with the center of the power transmission wire definedby the following relation:

15°≦θ≦180°

In the first aspect, preferably, the winding pitch p of the braided heatconducting wire heat dissipating belt around the power transmission wireis set within the following range with respect to an outer diameter D ofthe power transmission wire:

10D≦p≦30D

In the first aspect, preferably, a spiral rod is wound on the braidedheat conducting wire heat dissipating belt wound around the outercircumferential surface of the power transmission wire in a reversedirection to the winding direction of the braided heat conducting wireheat dissipating belt to secure the winding of the braided heatconducting wire heat dissipating belt.

In the first aspect, preferably, the heat conducting metal strand of thebraided heat conducting wire heat dissipating belt is a wire made ofaluminum or an aluminum alloy having a diameter of 0.3 mm to 3.0 mm.

In the first aspect, preferably, a plurality of the braided heatconducting wire heat dissipating belts are wound around the outercircumferential surface of the power transmission wire in the samedirection or so as to cross.

In the first aspect, preferably, an end of the braided heat conductingwire heat dissipating belt wound around the outer circumferentialsurface of the power transmission wire is wound around a front end of ananchor clamp to secure it.

In the first aspect, preferably, a braided heat conducting wire heatdissipating belt comprised of a heat conducting metal strand braided inthe form of a mesh belt is wound around the outer circumference of ajumper at a tension support of the power transmission wire, and the endof the braided belt member is wound around the front end of a jumperconnection of the anchor clamp to secure it.

According to a second form of the first aspect of the present invention,the conductive heat dissipation member of the heat dissipator for apower transmission wire has a conductive, surface-blackened heatdissipating spiral rod having a surface heat dissipation rate of 0.7 ormore spirally formed in the longitudinal direction so that it can beattached on the outer circumferential surface of the power transmissionwire in close contact thereto and the spiral rod is spirally woundaround the outer circumferential surface of the power transmission wireat a predetermined winding pitch.

In the second form of the first aspect of the present invention,preferably, the winding pitch p of the surface-blackened heatdissipating spiral rod is set within the following range with respect tothe outer diameter D of the power transmission wire:

10D≦p≦30D

In the second form of the first aspect of the present invention,preferably, the surface-blackened heat dissipating spiral rod to woundaround the outer circumferential surface of a jumper at the tensionsupport of the power transmission wire.

According to a third form of the first aspect of the present invention,preferably, a conductive heat dissipation member of the heat dissipatorfor a power transmission wire has a surface-blackened conductive heatdissipation member which is flexible, electrically conductive, and has asurface heat dissipation rate of 0.7 or more to be attached on the outercircumferential surface of the power transmission wire in close contactthereto, and the conductive heat dissipation member is spirally woundaround the outer circumferential surface of the power transmission wireat a predetermined winding pitch.

In the third form of the first aspect of the present invention,preferably, when the strand diameter of the outermost layer of the powertransmission wire is dd, the outer diameter of the surface-blackenedconductive heat dissipation member or the thickness in the diameterdirection is DD, the pitch of the twist of the strand of the outer layerof the power transmission wire is pp, and the winding pitch of theconductive heat dissipation member around the outer circumferentialsurface of the power transmission wire is PP, the following relationsstand:

0.8≦DD/dd≦2.0,

and

0.8≦PP/pp≦5.0

In the third form of the first aspect of the present invention,preferably, when the strand diameter of the outermost layer of the powertransmission wire is dd, the outer diameter of the surface-blackenedconductive heat dissipation member or the thickness of the diameterdirection is DD, the pitch of the twist of the strand of the outer layerof the power transmission wire is pp, and the winding pitch of theconductive heat dissipation member around the outer circumferentialsurface of the power transmission wire is PP, the following relationsstand:

1.0≦DD/dd≦1.2,

and

1.0≦PP/pp≦2.0

In the third form of the first aspect of the present invention,preferably, (1) the cross-section of the conductive heat dissipatingmember is circular, (2) the cross-section of the conductive heatdissipating member is a partially fan-like segment, (3) thecross-section of the conductive heat dissipating member is a hollowcircle, or (4) the cross-section of the conductive heat dissipatingmember is a hollow oval.

In the third form of the first aspect of the present invention,preferably, a groove for suppressing the formation of drops of water isformed along the circumference of the conductive heat dissipating memberhaving a circular cross-section.

In the third form of the first aspect of the present invention,preferably, the winding pitch p of the surface-blackened heatdissipating spiral rod around the power transmission wire is set to thefollowing range with respect to the outer diameter D of the powertransmission wire:

10D≦p≦30D

In the third form of the first aspect of the present invention,preferably, the surface-blackened heat dissipating spiral rod to woundaround the outer circumferential surface of the jumper at a tensionsupport of the power transmission wire.

According to a second aspect of the present invention, there is provideda power transmission wire having a heat dissipating means comprised of aconductive heat dissipation member having conductivity and a surfaceheat dissipation rate of 0.7 or more spirally wound around the outercircumferential surface at a predetermined winding pitch in closecontact thereto.

Preferably, the conductive heat dissipation member is treated to blackenits surface and delustered.

Further, preferably, the surface of the conductive heat dissipationmember is treated to make it hydrophilic.

Further, preferably, the conductive heat dissipation member has asurface which is artificially or naturally aged in advance.

Preferably, the conductive heat dissipation member is produced fromaluminum or an aluminum alloy.

Preferably, the power transmission wire is produced from any ofsteel-reinforced aluminum conductors (ACSR), steel-reinforced ultrathermo-resistant aluminum alloy conductors (UTACSR), Invar-reinforcedsuper or extra thermo-resistant aluminum alloy conductors (ZTACIR orXTACIR), and galvanized steel twisted wire.

Preferably, the conductive heat dissipation member is a braided heatconducting wire heat dissipating belt comprised of a heat conductingmetal strand braided in the form of a mesh belt.

Preferably, a plurality of braided heat conducting wire heatdissipating-belts are wound around the outer circumferential surface ofthe power transmission wire in close contact thereto in the samedirection or so as to cross.

Further, preferably, the conductive heat dissipation member is aconductive, surface-blackened heat dissipating spiral rod having asurface heat dissipation rate of 0.7 or more formed spirally in thelongitudinal direction so that it can be attached to the outercircumferential surface of the power transmission wire in close contactthereto.

Further, preferably, the conductive heat dissipation member is asurface-blackened conductive heat dissipation member which is flexible,electrically conductive, and has a surface heat dissipation rate of 0.7or more to be attached on the outer circumferential surface of the powertransmission wire in close contact thereto.

According to a third aspect of the present invention, there provided amethod of attaching a heat dissipator on a power transmission wirecomprising spirally winding a heat dissipation member havingconductivity and a surface heat dissipation rate of 0.7 or more aroundthe outer circumferential surface of an aerial line in close contactthereto at a predetermined winding pitch.

Preferably, the attachment work is carried out while transmitting powerthrough the power transmission wire.

Preferably, the conductive heat dissipation member is produced fromaluminum or an aluminum alloy.

Preferably, the conductive heat dissipation member is a braided heatconducting wire heat dissipating belt comprised of a heat conductingmetal strand braided in the form of a mesh belt.

Preferably, the braided heat conducting wire heat dissipating belt has awinding pitch giving a center angle θ of the winding width on thecircumference of the cross-section of the power transmission wire withthe center of the power transmission wire defined by the followingrelation:

15°≦θ≦180°

Further, preferably, the winding pitch p of the braided heat conductingwire heat dissipating belt around the power transmission wire is setwithin the following range with respect to an outer diameter D of thepower transmission wire:

10D≦p≦30D

Further, preferably, a plurality of the braided heat conducting wireheat dissipating belts are wound around the outer circumferentialsurface of the power transmission wire in the same direction or so as tocross.

Further, preferably, the conductive heat dissipation member is aconductive, surface-blackened heat dissipating spiral rod having asurface heat dissipation rate of 0.7 or more spirally formed in thelongitudinal direction so that it can be attached to the outercircumferential surface of the power transmission wire in close contactthereto.

Preferably, the winding pitch p of the surface-blackened heatdissipating spiral rod around the power transmission wire is set to thefollowing range with respect to the outer diameter D of the powertransmission wire:

10D≦p≦30D

Further, preferably, the conductive heat dissipation member is asurfaoe-blackened heat dissipating spiral rod which is flexible,electrically conductive, and has a surface heat dissipation rate of 0.7or more to be attached at the outer circumferential surface of the powertransmission wire in close contact thereto.

Preferably, when the strand diameter of the outermost layer of the powertransmission wire is dd, the outer diameter of the surface-blackenedconductive heat dissipation member or the thickness of the diameterdirection is DD, the pitch of the twist of the strand of the outer layerof the power transmission wire is pp, and the winding pitch of theconductive heat dissipation member around the outer circumferentialsurface of the power transmission wire is PP, the following relationsstand:

0.8≦DD/dd≦2.0,

and

0.8≦PP/pp≦5.0

Further, preferably, when the strand diameter of the outermost layer ofthe power transmission wire is dd, the outer diameter of thesurface-blackened conductive heat dissipation member or the thickness ofthe diameter direction is DD, the pitch of the twist of the strand ofthe outer layer of the power transmission wire is pp, and the windingpitch of the conductive heat dissipation member around the outercircumferential surface of the power transmission wire is PP, thefollowing relations stand:

1.0≦DD/dd≦1.2,

and

1.0≦PP/pp≦2.0

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view of the outer appearance of use of a braided heatconducting wire heat dissipating belt for an aerial line according to afirst embodiment of a heat dissipator for power transmission wire and apower transmission wire equipped with a heat dissipator of the presentinvention.

FIG. 2 is a sectional view of the aerial line and the braided heatconducting wire heat dissipating belt illustrated in FIG. 1.

FIG. 3 is an enlarged view of a first embodiment of the braid of thebraided heat conducting wire heat dissipating belt illustrated in FIG.1.

FIG. 4 is an enlarged view of a second embodiment of the braid of thebraided heat conducting wire heat dissipating belt illustrated in FIG.1.

FIG. 5 is a view of the outer appearance of use of a braided heatconducting wire heat dissipating belt for an aerial line according to asecond embodiment of the heat dissipator for a power transmission wireand the power transmission wire equipped with a heat dissipator of thepresent invention.

FIG. 6 is a sectional view of a third embodiment of the heat dissipatorfor a power transmission wire and the power transmission wire equippedwith a heat dissipator of the present invention.

FIG. 7 is a view of the state of use of a spiral rod for an anchor clampaccording to a fourth embodiment of the heat dissipator for a powertransmission wire and the power transmission wire equipped with a heatdissipator of the present invention.

FIG. 8A is a view of the cross-section of a line around which one heatdissipating spiral rod illustrated in FIG. 7 is wound, while FIG. 8B isa view of the cross-section of a line around which two heat dissipatingspiral rods illustrated in FIG. 7 are wound.

FIG. 9 is a view of the configuration of a first experimental example inthe present invention.

FIG. 10 is a graph of the result of the experimental example illustratedin FIG. 9.

FIG. 11 is a view of the outer appearance of a fifth embodiment of theheat dissipator for a power transmission wire and the power transmissionwire equipped with a heat dissipator of the present invention.

FIGS. 12A to 12C are sectional views of the aerial line and the heatdissipator used in the fifth embodiment illustrated in FIG. 11.

FIGS. 13A to 13E are views of the example of cross-section of the heatdissipator illustrated in FIG. 11.

FIG. 14 is a view of the outer appearance of a sixth embodiment of theheat dissipator for a power transmission wire and the power transmissionwire equipped with a heat dissipator of the present invention.

FIG. 15 is a view of the configuration of second to fourth experimentalexamples in the present invention.

FIG. 16 is a graph of a temperature reduction effect of the aerial lineas a first result of the experimental example illustrated in FIG. 15.

FIG. 17 is a graph of a corona hum characteristic of the aerial line asa second result of the experimental example illustrated in FIG. 15.

FIG. 18 is a graph of a wind noise characteristic of the aerial line asa third result of the experimental example illustrated in FIG. 15.

BEST NODE FOR WORKING THE INVENTION

Preferred embodiments of the present invention will be described withreference to the related figures.

FIRST EMBODIMENT

A first embodiment of the heat dissipator for a power transmission wire,power transmission wire equipped with a heat dissipator, and method forattaching a heat dissipator to power transmission wire of the presentinvention will be explained below by referring to FIG. 1 to FIG. 5.

FIG. 1 is a view of the outer appearance of the heat dissipator for apower transmission wire and the power transmission wire equipped with aheat dissipator of the first embodiment of the present invention. FIG. 2is a sectional view of the heat dissipator for a power transmission wireand the power transmission wire equipped with a heat dissipatorillustrated in FIG. 1. FIG. 3 and FIG. 4 are plan views of the braidedconductive heat dissipating wire illustrated in FIG. 1.

In FIG. 1 and FIG. 2, as an example of the power transmission wire, abraided heat conducting wire heat dissipating belt 1 is spirally woundaround the outer circumference of an aerial line 2 at a predeterminedpitch, and a spiral rod 3 is wound around the outer circumference of thebraided heat conducting wire heat dissipating belt 1 according to needin a reverse direction to the winding direction of the braided heatconducting wire heat dissipating belt 1 to suppress unraveling of thebraided heat conducting wire heat dissipating belt 1 wound around theperiphery of the aerial line 2. The spiral rod 3 is used as a means forpreventing the unraveling of the braided heat conducting wire heatdissipating belt 1.

The aerial line 2 is an already strung aerial line obtained by twistingtogether naked conductors such as for example steel-reinforced aluminumconductors (ACSR), steel-reinforced ultra thermo-resistant aluminumconductors (UTACSR), Invar-reinforced super thermo-resistant aluminumconductors (ZTACIR), Invar-reinforced extra thermo-resistant aluminumconductors (XTACIR), and galvanized steel twisted wire. Namely, thefirst embodiment refers to the technique of increasing the transmissioncapacity of an already strung aerial line 2.

(1) Material of Braided Heat Conducting Wire Heat Dissipating Belt 1

Below, the conditions of the material surface required for the braidedheat conducting wire heat dissipating belt 1 will be explained.

The braided heat conducting wire heat dissipating belt 1 has the role ofeffectively dissipating the heat of the aerial line 2 at first.Accordingly, it is necessary to produce the braided heat conducting wireheat dissipating belt 1 from a material having a good heat conductivity.

It is necessary to prevent an excessive increase of the weight of theaerial line as a whole by attaching the braided heat conducting wireheat dissipating belt 1 on the aerial line 2. Accordingly, it is desiredthat the braided heat conducting wire heat dissipating belt 1 be made ofa light weight material.

It is desired to increase the transmission capacity of the entire aerialline by attaching the braided heat conducting wire heat dissipating belt1 on the aerial line 2. Accordingly, it is desired that the braided heatconducting wire heat dissipating belt 1 be made of a conductivematerial.

The braided heat conducting wire heat dissipating belt 1 is preferablymade of a material having a good processability or installability(workability) when attaching it to the aerial line 2. Further, it todesirable that it be compatible with the aerial line 2 when attaching itto the aerial line 2 to make it integral with the aerial line 2.

The braided heat conducting wire heat dissipating belt 1 is preferablymade of a material having the same quality as that of the aerial line 2or a material where the electrochemical ionization potential is notremarkably different. The reason for this is that when for examplewinding a braided heat dissipating belt made of a material such ascopper or stainless steel on SCSR, if the electrochemical ionizationpotentials of the two are remarkably different, corrosion occurs due toelectrolytic corrosion and the outer layer strands of ACSR aredeteriorated. Note that the braided heat dissipating belt is not woundaround the surface of the aerial line locally and partially, butdesirably is wound continuously around the aerial line from theviewpoint of prevention of the accumulation of snow. The detailedreasons for this will be explained later.

The braided heat conducting wire heat dissipating belt 1 is used for along period of time together with the aerial line, so preferably has agood long term durability.

The braided heat conducting wire heat dissipating belt 1 preferably hasa low price.

In consideration of the above conditions, in the present embodiment, asthe braided heat conducting wire heat dissipating belt 1, use was madeof aluminum or an aluminum alloy. Note that the aerial line 2 is usuallyproduced from aluminum or an aluminum alloy such as steel-reinforcedaluminum conductors (ACSR) and the steel-reinforced ultrathermo-resistant aluminum conductors (UTACSR).

(2) Surface Heat Dissipation Rate of Braided Heat Conducting Wire HeatDissipating Belt

The heat dissipation rate (η) of the aerial line is a low value of about0.08 to 0.16 in the case of a new aluminum line immediately after theinstallation of the aerial line, but the surface of the line isblackened along with the elapse of time and the rate finally becomes avalue of about 0.9. This blackening is promoted by the application ofpower. The rate generally becomes about 0.7 to 0.8 in about 5 years to 7years. Therefore, desirably the braided heat conducting wire heatdissipating belt 1 also has a high heat dissipation rate from the start.At least 0.7 is necessary. Namely, the braided heat conducting wire heatdissipating belt 1 must be treated to blacken its surface in order toraise the heat dissipation characteristic and must have a surface heatdissipation rate of 0.7 or more. Note that the heat dissipation effectis insufficient by just dying the braided heat conducting wire heatdissipating belt 1 black. There must also not be gloss on the surface.

In order to blacken the surface of the aluminum wire material of thebraided strand of the braided heat conducting wire heat dissipating belt1, for example silicic acid is effective. If calcium sulfate or zinccarbonate or zinc sulfate is added to a sodium silicate solution, thesurface of the aluminum wire material can be changed to black in acertain range of concentration. Further preferably, if the surface ofthe aluminum wire material is sand blasted before applying theblackening treatment, a black surface having a further higher heatdissipation rate is obtained.

When a braided heat conducting wire heat dissipating belt 1 having sucha heat dissipation rate is wound around the outer circumferentialsurface of the aerial line 2 in close contact, the heat of the aerialline 2 is effectively conducted to the braided heat conducting wire heatdissipating belt 1 and the temperature of the aerial line 2 can belowered.

Preferably, the surface of the braided strand of the braided heatconducting wire heat dissipating belt 1 is roughened according to need,then subjected to a boehmite treatment or an alumite treatment or otherelectrochemical process or physical process to make it hydrophilic toprevent rain drops etc. from sticking to the surface of the aerial lineas much as possible and thereby improve the corona characteristic. Inother words, if rain drops etc. are formed on the surface of the aerialline, a state the same as that where numerous unevennesses are formed onthe surface of the aerial line is exhibited. The potential gradient(value having absolute value equal to the field intensity, but with areverse sign) of these projections becomes larger and the coronadischarge occurs earlier, therefore the corona characteristic isdegraded. When the surface of the aerial line is treated to make ithydrophilic, the contact angle of the rain drops with the surface of theaerial line becomes large and the contact angle of the surface of theaerial line becomes large, so unevenness is no longer formed on thesurface of the aerial line, therefore the potential gradient of thesurface of the aerial line becomes low, the corona discharge voltagebecomes high, and the corona characteristic can be improved.

(3) Dimensions of Braided Heat Conducting Wire Heat Dissipating Belt

As shown in FIG. 3, the braided heat conducting wire heat dissipatingbelt 1 comprises heat conducting wire made of aluminum or aluminum alloyor wire to which they are applied having a thickness (diameter) of about0.3 to 3.0 mm braided in the form of a mesh belt using a strand 1 a ofthe braid as the warp and a strand 1 b as the weft to form a long heatdissipating belt. For the so-called selvedge 1 a 0 of the warp at thetwo side edges of the braided heat conducting wire heat dissipating belt1 in the warps 1 a, it is possible to use a strand having a thicknessdifferent from that of the other warp strands 1 a for holding the shapeand strength of the braided heat conducting wire heat dissipating belt1. The selvedges 1 b 0 of the weft strand ends at the two side edges ofthe braided heat conducting wire heat dissipating belt 1 desirably arebent to circular curves as shown in FIG. 3 to prevent the generation ofa corona.

The thickness of the braided strands of the braided heat conducting wireheat dissipating belt 1 must be from 0.3 mm to 3.0 mm as described abovein view of the mechanical strength and the electrical characteristics.The work of winding the braided heat conducting wire heat dissipatingbelt 1 is done at the high place at which the aerial line 2 is strungbetween the towers, therefore in order to facilitate the winding work,the braided heat conducting wire heat dissipating belt 1 must haveflexibility. Further, since it is used exposed to the outdoors for along period of time, it is required that it not be reduced in strengthdue to corrosion. From this viewpoint, the thickness of the braidedstrand must be 0.3 mm or more. Further, when considering the fact thatthere may also be a case where the braided heat conducting wire heatdissipating belt 1 is wound around the aerial line 2 manually or thelike, the manual winding work would become difficult if the thickness is3.0 mm or more. Further, in view of the electrical characteristics, ifthere are thick projections on the surface of the aerial line 2, coronais easily generated and becomes the cause of corona noise. From theviewpoint of the mechanical strength and electrical characteristics, therange of the thickness of the braided strand should be 0.3 mm as a lowerlimit and 3.0 mm as an upper limit.

The size of meshes of the mesh belt braid of the braided heat conductingwire heat dissipating belt 1 is suitably selected according to the outerdiameter dimension of the aerial line 2 to which it is applied.

The braid of the braided heat conducting wire heat dissipating belt 1may be also a twill braid in which two warps and wefts each arealternately braided as shown in FIG. 4 or may be a mat braid (notillustrated) or other braid in addition to the plain weave braid shownin FIG. 3.

Space between warps and wefts: The number of the braids is expressed bythe unit of “meshes” according to JIS G3555 which means the numberwithin a 25.4 mm square. The number of stitches N is found byN=25.4/(W+d). The number of stitches N is the number of the stitches atone 25.5 mm side. W is the stitch reference dimension, that is, thespace (mm) between the warps and wefts, while d indicates the referencewire diameter (mm). In the present embodiment, as explained above, d ismade equal to 0.3 to 3.0 mm, but actually a range of N=7.06 to 25.4 isused, and W and d satisfying this N are found. By this, d becomes equalto 0.315 to 2.8 mm, and W becomes equal to 0.600 to 4.5 mm.

(4) Method of Attaching Braided Heat Conducting Wire Heat DissipatingBelt

In order to wind the braided heat conducting wire heat dissipating belt1 around the aerial line 2, it is possible to use a self-propelledrobot, a lashing machine, or the like to continuously wind it andthereby install it in a short time and possible to install it by withoutwholly stopping the power transmission of all aerial lines 2 and bystopping just line.

Note that when winding the braided heat conducting wire heat dissipatingbelt 1 around the aerial line 2, from the viewpoint of the prevention ofthe accumulation of snow, the belt is not locally and partially wound,but desirably is continuously wound. For example, in the means forpreventing snow tubes disclosed in Japanese Unexamined PatentPublication (Kokai) No. 64-81110 and Japanese Unexamined PatentPublication (Kokai) No. 64-81111, the mesh-like braided aluminum wire isonly wound in a direction orthogonal to the longitudinal direction ofthe aerial line. In particular, it is just intermittently wound,therefore there is a high possibility of the sticking snow growing intoa snow tube at the parts around which the aluminum wire is not wound dueto its sliding around the surface of the aerial line. Particularly, inthe case of an aerial line of a type where the outer layer strands ofthe aerial line are formed by segment strands and when twisted togethergive a substantially cylindrical, so-called smooth body type with notwisted grooves, there is a tendency for snow to particularly easilyaccumulate. Therefore, in the first embodiment of the present invention,the braided heat conducting wire heat dissipating belt 1 is continuouslyhelically (spirally) wound around the surface of the aerial line 2 alongthe longitudinal direction to thereby effectively prevent the stickingsnow from sliding around the line.

(5) Relationship Between Winding Pitch P and Center Angle θ of WindingWidth w

The winding pitch p of the braided heat conducting wire heat dissipatingbelt 1 around the aerial line 2 is set to a winding pitch, on thecircumference of the cross-section of the power transmission wire shownin FIG. 2, giving an angle of the winding width w on the circumferenceof the aerial line 2 with the center of the aerial line 2, that is, thecenter angle θ, of at least 15°. Preferably, the winding pitch p isdetermined to give a center angle θ of the winding width defined by thefollowing relation 1:

15°≦θ≦180°  (1)

When the winding pitch p is set to give a center angle θ of the windingwidth W of the braided heat conducting wire heat dissipating belt 1occupied on the circumference of the cross-section of the aerial line 2as defined by relation 1, the effect of preventing the accumulation ofsnow on the aerial line 2 by the braided heat conducting wire heatdissipating belt 1 to not degraded and the increase of the total weightof the line is suppressed. If the center angle θ of the winding width Wof the braided heat conducting wire heat dissipating belt 1 becomeslarger than 180°, the effect of promoting sloughing off of the snowbecomes small, while if the center angle θ is made smaller than 15°, aconspicuous heat dissipation effect cannot be obtained.

The reason for the above will be explained in further detail below.

Since the braided heat conducting wire heat dissipating belt 1 is formedas a mesh belt, the adhered snow does not easily slough off, thereforeif the braided heat conducting wire heat dissipating belt 1 is woundaround the entire surface of the aerial line, the outer diameter of theline will be increased, sticking of the snow will become easier, andtherefore the snow adhered to the upper portion of the line will beliable to grow into a snow tube as the line twists. When the braidedheat conducting wire heat dissipating belt 1 is spirally wound aroundthe outer circumferenoe of the aerial line 2, a separating force actsbetween the easily sliding snow sticking to the surfaces of the aerialline 2 exposed between the spirals and the snow sticking on the braidedheat conducting wire heat dissipating belt 1. The snow sticking to thesurfaces of the aerial line 2 exposed from the braided heat conductingwire heat dissipating belt 1 first sloughs off, so will not grow into anexcessively large snow tube. Accordingly, from the viewpoint of thebalance of the separating force, the maximum center angle of the windingwidth W, on the circumference of the cross-section of the aerial line 2,of the braided heat conducting wire heat dissipating belt 1 must be setto 180° or less. When the center angle θ of the winding width W becomeslarger than 180°, the amount of the snow sticking to the braided heatconducting wire heat dissipating belt 1 becomes large, so the effect ofpromoting sloughing off of the snow is degraded. If the center angle ofthe winding width W of the braided heat conducting wire heat dissipatingbelt 1 is set to 180° or less, the increase of the weight can besuppressed to 50% or less in comparison with the case where it is woundaround the entire surface of the aerial line 2.

If the center angle θ of the winding width W of the braided heatconducting wire heat dissipating belt 1 on the circumference of thecross-section of the aerial line 2 is made smaller than 15°, whenassuming a case where for example the braided heat conducting wire heatdissipating belt 1 is wound around standard power transmission wirecomprised of steel-reinforced aluminum conductors (ACSR) of 410 mm² area(outer diameter: 28.5 mm) as the aerial line 2, the winding width W whenthe center angle θ is 15° is about 3.7 mm, but this winding width W isthe lowest limit when considering the reduction of the mechanicalstrength due to particularly the corrosion action with usage over a longperiod of time. If the width W of the braided heat conducting wire heatdissipating belt 1 is too small, even if it is wound around the entireouter circumferential surface of the aerial line 2, a remarkable heatdissipation effect cannot be expected.

(6) Relationship Between Winding Pitch p and Outer Diameter D of AerialLine 2

The winding pitch p of the braided heat conducting wire heat dissipatingbelt 1 around the aerial line 2 is desirably set to a value defined bythe following relation 2 in relation to the outer diameter D of theaerial line 2. It is economical and safe in the case of winding workutilizing a lashing machine or the like.

10D≦p≦30D  (2)

The grounds for relation 2 will be explained. If the winding pitch p istoo short, the amount of winding of the braided heat conducting wireheat dissipating belt 1 around the aerial line 2 becomes large and theweight of the line is increased, which is not preferred. Further, if thewinding pitch p is short, when the braided heat conducting wire heatdissipating belt 1 is wound over the aerial line 2 by utilizing alashing machine or the like, the installation time is greatly increased,so a lashing machine cannot be utilized. In certain cases, the belt mustbe installed manually, which is disadvantageous in view of economy. Forthese reasons, a winding pitch p of 10D or less is inconvenient and thepitch must be at least 10D.

The safety of the installation speed when a lashing machine or the likeis used is ensured by setting the winding pitch p to 30D or less. Then,no sag of the braided heat conducting wire heat dissipating belt 1 woundaround the aerial line 2 occurs. For example, when steel-reinforcedaluminum conductors (ACSR) of 410 mm² area (outer diameter: 28.5 mm) areused for the aerial line 2 and the braided heat conducting wire heatdissipating belt 1 is wound around the ACSR, the pitch becomes 855 mm at30D. When the outer diameter D of the aerial line 2 becomes furtherlarger, the winding pitch p also becomes longer and the traveling speedof the winding machine also becomes faster, so the risk is increased,which is not preferred. Further, if the winding pitch p exceeds 30D, dueto the sagging of the braided heat conducting wire heat dissipating belt1, the braided heat conducting wire heat dissipating belt 1 wound at thebottom of the aerial line 2 becomes slack and separates from the surfaceof the aerial line 2, so the heat dissipation function of the aerialline 2 is reduced.

In order to prevent the unraveling of a winding start end 1 c of thebraided heat conducting wire heat dissipating belt 1 around the aerialline 2, as illustrated in FIG. 1, one or more armor rods or other spiralrods such 3 a are wound upon the end 1 c of the braided heat conductingwire heat dissipating belt 1 to hold the end 1 c of the braided heatconducting wire heat dissipating belt 1 or another suitable fixture etc.is used to secure it.

The middle part of the braided heat conducting wire heat dissipatingbelt 1 wound around the aerial line 2 is held by winding one or morearmor rods or other spiral rods 3 b upon the braided heat conductingwire heat dissipating belt 1 at suitable intervals so that slack doesnot occur or another suitable fixture etc. is used to secure it.

As described above, by winding the braided heat conducting wire heatdissipating belt 1 around the surface of the outer circumference of thealready strung aerial line 2 in direct close contact thereto, the heatof the surface of the power transmission wire is conducted to thebraided heat conducting wire heat dissipating belt 1 of aluminum oraluminum alloy having a high heat conductivity. As illustrated in FIG. 3and FIG. 4, the overall surface area of the braided heat conducting wireof the braided heat conducting wire heat dissipating belt 1 is extremelylarge, therefore the heat dissipation effect from the surface of theaerial line 2 is increased by using the aerial line 2. As a result, itbecomes possible to pass a current of more than the previouslypermissible current through the already strung aerial line 2 and therebyincrease the transmission capacity of the already strung aerial line.Further, the current also passes through the braided heat conductingwire heat dissipating belt 1 itself using the conductive aluminum,aluminum alloy, or the like, therefore the transmission capacity of theentire aerial line can be increased by the amount of the current flowingthrough the braided heat conducting wire heat dissipating belt 1.Namely, the braided heat conducting wire heat dissipating belt 1 itselftransmits power as part of the aerial line 2 in addition to the increaseof the transmission capacity of the aerial line 2 itself due to the heatdissipation of the aerial line 2.

The braided heat conducting wire heat dissipating belt 1 using thealuminum or aluminum alloy is light, therefore even if the braided heatconducting wire heat dissipating belt 1 is wound around the aerial line2, no excessive weight is applied on the power transmission wire.Further, aluminum is highly flexible, so the attachment of the braidedheat conducting wire heat dissipating belt 1 on the aerial line 2 iseasy.

SECOND EMBODIMENT

A second embodiment of the heat dissipator for a power transmissionwire, power transmission wire equipped with a heat dissipator, andmethod of attaching a heat dissipator on a power transmission wire ofthe present invention will be explained by referring to FIG. 5.

FIG. 5 is a view of an example of securing the end of the winding endpart of the braided heat conducting wire heat dissipating belt 1 in thevicinity of an anchor clamp 4 at the tension anchor for anchoring by theanchor clamp 4 the aerial line 2 around which the braided heatconducting wire heat dissipating belt 1 is wound.

The middle part of the braided heat conducting wire heat dissipatingbelt 1 wound around the outer circumference of the aerial line 2 is heldby winding the spiral rod 3 on the braided heat conducting wire heatdissipating belt 1. The end 1 d of the braided heat conducting wire heatdissipating belt 1 is wound around the front end 4 a of the anchor clamp4 beyond the end of the aerial line 2 and secured by a securing device5. If the braided heat conducting wire heat dissipating belt 1 is alsowound around the anchor clamp 4 portion in this way, the heatdissipation of the anchor clamp 4 also becomes possible and overheatingof the anchor clamp 4 can also be prevented. Note that the winding pitchof the braided heat conducting wire heat dissipating belt 1 around theanchor clamp front end 4 a to preferably made smaller than the windingpitch at the surface of the aerial line 2, and that part fixed by asuitable clamp device.

In this way, by winding the spiral rod 3 upon the braided heatconducting wire heat dissipating belt 1 wound around the outercircumference of the aerial line 2 in the reverse direction to thewinding direction of the braided heat conducting wire heat dissipatingbelt 1, the braided heat conducting wire heat dissipating belt 1 woundaround the aerial line 2 is secured and unraveling of the end 1 c of thewinding start part of the braided heat conducting wire heat dissipatingbelt 1 is prevented, thus the slack of the middle part of the braidedheat conducting wire heat dissipating belt 1 wound around the aerialline 2 can be prevented.

FIG. 5 shows an embodiment of suppressing a rise of the temperature of ajumper 8 by winding the braided heat conducting wire heat dissipatingbelt 1 around the jumper 8 at the tension support of the aerial line. Bywinding the braided heat conducting wire heat dissipating belt 1 aroundthe outer circumference of the jumper 8 connected to the anchor clamp 4,the overheating of the jumper 8 is prevented, and an increase of thetransmission capacity of the aerial line can be achieved. Also,overheating of the jumper connection 6 of the anchor clamp 4 isprevented by the end 1 e of the braided heat dissipating belt 1 woundaround the jumper 8, the end 1 e being secured by the securing device 7.

Note that, in FIG. 5, only the braided heat dissipating belt 1 is woundaround the jumper 8 and that the illustration of the winding of thespiral rod on the braided heat dissipating belt 1 in this case isomitted, but the spiral rod is wound around the outer circumference ofthe braided heat conducting wire heat dissipating belt 1 wound aroundthe outer circumference of the jumper 8 in the reverse direction to itswinding direction like the case where the braided heat conducting wireheat dissipating belt 1 is wound around the outer circumference of theaerial line 2 and then the spiral rod 3 is wound upon this in thereverse direction to the winding direction of the braided heatconducting wire heat dissipating belt 1.

The braided heat conducting wire heat dissipating belt 1 is highlyflexible, so can be easily attached on the anchor clamp 4 and the jumper8 etc. having a complex structure and also can prevent overheating ofthe anchor clamp 4 and the jumper 8. The braided heat conducting wireheat dissipating belt 1 using aluminum or aluminum alloy is light, so noexcessive weight is applied even if it is used for the heat dissipationof the anchor clamp and the jumper.

THIRD EMBODIMENT

A third embodiment of the heat dissipator for a power transmission wire,power transmission wire equipped with a heat dissipator, and method ofattaching a heat dissipator on a power transmission wire of the presentinvention will be explained by referring to FIG. 6.

FIG. 6 shows the cross-section of the power transmission wire obtainedby winding the braided heat conducting wire heat dissipating belt 1around a relatively wide aerial line 2, for example the aerial line 2having a diameter D of for example about 52.8 mm.

In the third embodiment, there is not only one braided heat conductingwire heat dissipating belt 1 wound around the outer circumference of theaerial line 2. Two braided heat conducting wire heat dissipating belts11 and 12 are wound at opposite positions of the outer circumference ofthe aerial line 2 in the same direction so as to face each other on thediameter line of the aerial line 2. On the circumference of thecross-section of the aerial line 2 shown in FIG. 6, a center angle θ1 ofa winding width W1 occupied on the circumference of the line of thefirst braided heat dissipating belt 11, a center angle θ2 of a windingwidth W2 occupied on the circumference of the line of the second braidedheat dissipating belt 12, and a center angle θ3 of the interval betweenthe winding widths W1 and W2 of the two belts, that is, the braided heatdissipating belt 11 and the braided heat dissipating belt 12, areselected as defined by the following relation:

15°≦θ1≦θ2≦θ3  (3)

The two braided heat dissipating belts 11 and 12 to be wound around theaerial line 2 may also be wound by bringing the braided heat dissipatingbelts 11 and 12 in close contact with each other by setting the centerangle θ3 of the interval between two lines of the braided heatdissipating belts 11 and 12 to zero. The braided heat dissipating belts11 and 12 wound around the outer circumference of the aerial line 2 inclose contact in this way, in the same way as the first embodimentexplained by referring to FIG. 1 and FIG. 2, have the spiral rod 3 woundaround them to hold braided heat dissipating belts 11 and 12 or they aresecured by other suitable fixtures.

The winding direction of the two braided heat dissipating belts 11 and12 around the outer circumference of the aerial line 2 may be such thatthe two braided heat dissipating belts 11 and 12 are wound crossing eachother on the outer circumferential surface of the aerial line 2. In thiscase, the end of the winding start part around the aerial line 2 issecured by winding the spiral rod or holding this by another suitablefixture or the like in the same way as the first embodiment, but themiddle parts of the two braided heat conducting wire heat dissipatingbelts 1 wound around the aerial line 2 are held by superposing the upperbraided heat conducting wire heat dissipating belt over the lowerbraided heat conducting wire heat dissipating belt to hold it, thereforethe winding of the spiral rod can be omitted, the increase of the loadapplied on the aerial line 2 becomes smaller, and the increase of thesag of the aerial line 2 accompanying the increase of the weight becomessmaller.

Of course, in order to more reliably hold and secure the braided heatdissipating belts 11 and 12 wound around the aerial line 2, it is alsopossible to wind the spiral rod upon the two braided heat dissipatingbelts 11 and 12 wound crossing each other.

In the first to third embodiments, an example in which one or twobraided heat conducting wire heat dissipating belts 1 were wound arounda single aerial line 2 was explained, but it is also possible to dividemultiply arranged aerial lines into sub spans consisting of the sectionsbetween spacers securing the attached multiple lines to each other andto wind (attach) braided heat conducting wire heat dissipating belts 1around these.

FOURTH EMBODIMENT

A fourth embodiment of the heat dissipator for a power transmissionwire, power transmission wire equipped with a heat dissipator, andmethod of attaching a heat dissipator on a power transmission wire ofthe present invention will be explained by referring to FIG. 7.

FIG. 7 is a view illustrating the outer appearance of a spiral rod 10made of aluminum or aluminum alloy shaped helically in advance woundaround the outer circumference of an aerial line 2 in the same way asthe braided heat conducting wire heat dissipating belt 1 in place of thebraided heat conducting wire heat dissipating belt 1.

The spiral rod 10 also uses aluminum or aluminum alloy satisfying thematerial conditions in the same way as those for the braided heatconducting wire heat dissipating belt 1, blackening treatment is appliedto the surface, and the surface heat dissipation rate is set at 0.7 ormore. The surface of the spiral rod 10 made of aluminum or aluminumalloy is treated to blacken it in the same way as the blackeningtreatment of the braided heat conducting wire heat dissipating belt 1 inthe first embodiment by for example treating the surface with a sodiumsilicate solution containing calcium sulfate or zinc carbonate or zincsulfate to discolor the surface black and thus obtain a black surfacehaving a high heat dissipation rate.

Note that the spiral rod 10 can be increased in hydrophilicity of itssurface by an electrochemical process or a physical process according toneed to improve the corona characteristic.

One or more spiral rods 10 formed in this way are continuously woundaround the outer surface of the aerial line 2 in close contact in thelongitudinal direction at a twist pitch p. Other than this, the samematters considered for the braided heat conducting wire heat dissipatingbelt 1 are also applied to the spiral rod 10. For example, whenexplaining an example thereof, the surface-blackened heat dissipatingspiral rod 10 is wound around the power transmission wire so that thewinding pitch p becomes within the range of (10D≦p≦30D) with respect tothe outer diameter D of the aerial line 2. As explained above for thebraided heat conducting wire heat dissipating belt 1, for the spiral rod10 as well, if the winding pitch p is a too short 10D or less, theamount of winding of the spiral rod 10 becomes large, so not only to thetotal weight of the aerial line increased, but also the installationtime is greatly increased when the winding work is carried out byutilizing a lashing machine or the like, so it becomes disadvantageousfrom the viewpoint of economy. Accordingly, 10D or more is required forthe winding pitch p. Conversely, if the winding pitch p is a too long30D or more, the traveling speed of the winding machine becomes fast,therefore the risk is increased, which is not preferred. The safety ofthe installation speed is secured by setting the winding pitch p to 30Dor less.

The anchor clamp 4, jumper connection 6, and jumper 8 are similar tothose explained referring to FIG. 5. Note, in the case of the spiral rod10, it is not particularly necessary to secure the end as in the braidedheat conducting wire heat dissipating belt 1, therefore the windingsecuring device 5 illustrated in FIG. 5 is eliminated.

In the present embodiment, the spiral rod 10 exhibits a similar effectto that by the braided heat conducting wire heat dissipating belt 1.

FIG. 8A shows an embodiment in which one surface-blackened heatdissipating spiral rod 10 is wound around the outer circumferentialsurface of the aerial line 2, and FIG. 8B shows an embodiment in whichtwo heat dissipating spiral rods 10, that is, 10 a and 10 b, are woundaligned with each other.

The aerial line 2 illustrated in FIGS. 8A and 8B is constituted by thegeneral structure of an aerial line, that it, a core line 2A, anintermediate layer line 2B, and an outer layer line 2C. Of course, theaerial line 2 to which the present invention is applied is not limitedto a power transmission wire having the structure illustrated in FIGS.8A and 8B and may be power transmission wires having a variety ofstructures.

The aerial line 2 is formed by for example steel-reinforced aluminumconductors (ACSR), steel-reinforced ultra thermo-resistant aluminumconductors (UTACSR), Invar-reinforced super or extra thermo-resistantaluminum conductors (ZTACIR or XTACIR), or galvanized steel twistedwire.

In the present embodiment as well, a surface-blackened heat dissipatingspiral rod 10 can be wound around the aerial line 2 to promote the heatdissipation of the surface of the aerial line 2 and suppress the rise ofthe temperature of the aerial line 2. For example, when the spiral rod10 is wound around the aerial line 2, it becomes possible to send acurrent more than the past permissible current through the aerial line 2and increase the transmission capacity of an already strung aerial line.In addition, current also flows through the spiral rod 10 itself, so thetransmission capacity is further increased.

Note that, as shown by the experimental examples explained later, theeffect of suppressing the rise of the temperature of the line has a moreconspicuous temperature reduction effect the higher the surfacetemperature of the aerial line.

The surface-blackened heat dissipating spiral rod 10 is shaped helicallyin advance, so can be easily wound around the outer circumference of theaerial line 2. For example, the spiral rod 10 can be continuously woundaround an already strung aerial line 2 by a self-propelled robot, alashing machine, or the like. At this time, it to possible to installthe spiral rod 10 on aerial lines 2 in a short time by just stoppingtransmission over one line and not stopping the transmission over all ofthe aerial lines.

The spiral rod 10 made of aluminum or aluminum alloy is light, thereforeeven if it is wound around the aerial line 2, there is no excessiveincrease of the weight load and an increase of the transmission capacitycan be economically realized without replacing an already strung aerialline.

Although the illustration was omitted in FIG. 7, a spiral rod 10 canalso be wound around the outer circumference of the jumper 8. As aresult, the heat dissipation effect of the jumper 8 is increased, andthe transmission capacity of the jumper 8 can be increased.

FIRST EXPERIMENTAL EXAMPLE

An experimental example of the fourth embodiment explained above will beexplained by referring to FIG. 9.

FIG. 9 is a view of an experiment in which a constant current is passedthrough a part A of the aerial line 2 upon which the above-mentionedsurface-blackened spiral rod 10 is laid and a part B of the aerial line2 on which the spiral rod 10 is not laid from a transformer Tr and thesurface temperature of the aerial line 2 at the part A and the surfacetemperature of the aerial line 2 at the part B are measured. An aerialline 2 having a length of 150 m was bent back at 75 m. A spiral rod 10made of aluminum was wound around the aerial line 2 at the section A bythe method illustrated in FIG. 7. The aerial line 2 at the section A andthe aerial line 2 at the section B were laid in parallel.Steel-reinforced aluminum conductors (ACSR) were used as the aerial line2.

The sectional area of the ACSR was 410 mm². Accordingly, the outerdiameter D of the ACSR was 28.5 mm. One surface-blackened heatdissipating spiral rod 10 made of aluminum having a diameter (thickness)of 6 mm and a spiral pitch of 300 mm was continuously wound around theaerial line 2 of the ACSR in the part of the section A, i.e., 75 m.

The surface temperature differences of the line at different parts atthe winding zone A and the non-winding zone B were measured and comparedin the state where the current of 1500 A was passed from the transformerTr outdoors under an environment of a wind speed of about 0.8 m/s.

FIG. 10 is a graph showing the result of the experiment illustrated inFIG. 9. The abscissa indicates the length (m) of the aerial line, whilethe ordinate indicates the surface temperature (° C.) of the aerialline. The curves A1 to A3 indicate the surface temperatures of theaerial line at the section A with respect to the length direction, andwhile the curves B1 to B3 indicate the surface temperatures of theaerial line at the section B with respect to the length direction. Thecurves A1 and B1 show the result of measurement of the characteristic ofthe temperature rise in the still low temperature state of the initialstate after an elapse of 21.5 minutes from the start of the supply ofthe power, the curves A2 and B2 show the result of measurement of thecharacteristic of the temperature rise of the state during thetemperature rise after an elapse of 50.1 minutes from the start of thesupply of the power and where the highest temperature has not yet beenreached, and the curves A3 and B3 show the result of measurement of thecharacteristic of the temperature rise of the state where the highesttemperature has substantially been reached after an elapse of 80 minutesfrom the start of the supply of power.

In FIG. 10, when comparing the temperatures of the line at the windingzone A at which the heat dissipating spiral rod 10 was wound and thenon-winding zone B at which it was not wound, the temperature of theaerial line in the state where the temperature of the line rose to ahigh temperature after the elapse of 80 minutes from the start of thesupply of the power was 140° C. at the position indicated by S₂=120 m(vertical broken line position) measured from for example the startpoint S₀, at the non-winding zone shown by the curve B3, while was 115°C. at the position indicated by S₁=30 m (vertical broken line position)measured from for example the start point S₀ at the winding zone A, soit was confirmed that the temperature of the aerial line around whichthe heat dissipating spiral rod 10 was wound became lower by at least25°. Note that, S₁=30 m and S₂=120 m indicate equal distances from thetwo ends of the aerial line 2 having a total length of 150 m.

In the state where the temperatures of the lines indicated by the curvesA2 and B3 have not yet reached the high temperature, the temperature ofthe line at the vertical broken line position indicated by S₂=120 m atthe non-winding zone B was 110° C., while the temperature of the line atthe vertical broken line position indicated by S₁=30 m at the windingzone A was 100° C., so the temperature reduction effect thereof was 10°C. In the case of the state where the temperatures of the line indicatedby the curves A1 and B1 are in the low temperature zone, the temperatureof the line at the vertical broken line position indicated by S₂=120 mat the non-winding zone B was 70° C., while the temperature of the lineat the vertical broken line position indicated by S₁=30 m at the windingzone A was 65° C., so the temperature reduction effect thereof was 5° C.

In this way, it was seen that the higher the surface temperature of theline, the larger the temperature reduction effect of the line byproviding the spiral rod 10 on the aerial line 2, and the lower thesurface temperature, the smaller the effect.

FIFTH EMBODIMENT

As a fifth embodiment of the present invention, an aerial line, aerialground line, etc. will be given as examples of the power transmissionwire equipped with a heat dissipator. A heat dissipator to be laid on anaerial line, aerial ground line, etc. (hereinafter referred to as thepower transmission wire) will be given as examples of the heatdissipator for a power transmission wire.

FIG. 11 is a view of the outer appearance of a heat dissipator for apower transmission wire and a power transmission wire equipped with aheat dissipator of the fifth embodiment of the present invention, FIGS.12A to 12C are sectional views of the power transmission wire equippedwith the heat dissipator illustrated in FIG. 11, and FIGS. 13A to 13Eare sectional views of the heat dissipator for a power transmission wireillustrated in FIGS. 12A to 12C.

FIG. 11 particularly illustrated the case of an aerial line as a powertransmission wire 101. A heat dissipator 102 is laid on the aerial line101. The heat dissipator 102 is secured by a heat dissipator securingring 103, while the heat dissipator securing ring 103 is secured to ananchor clamp 104. Further, the heat dissipator 102 is also laid upon ajumper 106, and the heat dissipator 102 is secured to a jumper clamp 105by the heat dissipator securing ring 103.

A detailed description will be given of the aerial line 101 and the heatdissipator 102 next.

Example of the sectional shapes of the aerial line 101 and the heatdissipator 102 are illustrated in FIGS. 12A to 12C.

FIG. 12A shows the sectional shape in the case where a conductive heatdissipating wire of the heat dissipator 102 comprised of a rod having ahollow oval cross-section is wound around the outer circumferentialsurface of the aerial line 101. In this example, as the aerial line 101,the case of strands having a circular cross-section in the same way asthose illustrated in FIGS. 8A and 8B was shown. The aerial line 101comprises core strands 101A, intermediate layer strands 110B, and outerlayer strands 101C. These strands 101A, 101B, and 101C are twisted inthe form of a spiral along the axial direction. For example, the aerialline 101 comprises strands of steel-reinforced aluminum conductors(ACSR) having an outer diameter indicated by d=diameter of 2 to 4 mm (φ2to φ4.8) twisted together as the core strands 1A. The pitch pp of twistof the outer layer strands is 40 to 90 times the outer layer stranddiameter dd (pp=40 to 90 dd).

FIG. 12B shows an example of winding conductive heat dissipating wires110 a and 110 b of two heat dissipators around a low noise line 120having projecting strands 111 for lowering the noise on the outermostcircumference, referred to as a “low noise aerial line”, for the purposeof the lowering the noise in addition to the heat dissipation effect,disclosed in Japanese Unexamined Patent Publication (Kokai) No.6-302223. In this case, the conductive heat dissipating wires 102 a and102 b of the heat dissipators 102 are wound around the aerial line 120at the same winding pitch as the pitch of twist of the projectingstrands 111. The structure of the low noise line 120 itself is similarto that disclosed in Japanese Unexamined Patent Publication (Kokai) No.6-302223. The conductive heat dissipating wires 102 a and 102 b of theheat dissipators 102 promote the heat dissipation of the low noise line120 and lower the noise.

FIG. 12C shows the method of winding heat dissipators capable ofimproving the corona characteristic in addition to the heat dissipationeffect. When two conductive heat dissipating wires 102 a and 102 b arewound around the outer circumferential surface of the aerial line 101 inclose contact, the aspect ratio of the projection becomes smaller thanthe case of one conductive heat dissipating wire, so the electric fieldis reduced and the corona noise characteristic is improved. Thistechnique applies the technique disclosed in Japanese Unexamined PatentPublication (Kokai) No. 57-98907 (Japanese Examined Patent Publication(Kokoku) No. 58-38884), but in the present embodiment, in addition tothe prevention of the corona noise, the two conductive heat dissipatingwires 102 a and 102 b having the above characteristics promote the heatdissipation of the aerial line 101. The aerial line 101 illustrated inFIG. 12C is the same as the aerial line 101 illustrated in FIG. 12A.

Of course, the aerial line 101 is not limited to the structuresillustrated in FIGS. 12A to 12C and may be the aerial lines 2illustrated in FIGS. 8A and 8B too. Further, lines having other variousstructures, for example, an aerial power transmission wire obtained bytwisting and combining segment strands, can be applied. For example, asthe power transmission wire 101, use can be made of a line obtained bysuperimposing a plurality of layers of strands having the same sectionalarea on each other, a laminate of strands having a small sectional areacorresponding to the core strands 101A and strands having a largesectional area corresponding to the outer layer strands 101C, etc.

The aerial line 101 is for example comprised of steel-reinforcedaluminum conductors (ACSR), steel-reinforced ultra thermo-resistantaluminum conductors (UTACSR) excellent in the thermo-resistantcharacteristic, Invar-reinforced super or extra thermo-resistantaluminum conductors (ZTACIR or XTACIR) excellent in thermo-resistanceand having a small linear expansion coefficient, galvanized steeltwisted wire used for aerial ground lines, an aerial ground linecontaining optical fibers, etc. For example, in the case of an aerialground line containing optical fibers, a structure is exhibited in whichthe core strands 101A illustrated in FIG. 12A correspond to the opticalfibers and the aerial ground line surrounds the optical fibers as theouter layer strands 101C is exhibited.

As the heat dissipator 102 laid upon the outer layer of the aerial lines101 and 120, a single conductive heat dissipator 102 can be provided asillustrated in FIG. 12A or two same conductive heat dissipating wires102 a and 102 b can be provided together as illustrated in FIGS. 12B and12C. The individual conductive heat dissipating wires constituting theheat dissipator 2 can take various sectional shapes illustrated in FIGS.13A to 13E, details of which will be explained later.

The conductive heat dissipating wire of the heat dissipator 102 isspirally wound around the outer circumferential surface of the powertransmission wire 101 at the winding pitch PP. The heat dissipating wireof the heat dissipator 102 is wound in an open state without completelycovering the outer surface of the power transmission wire 101.

By winding the heat dissipator 102, that is, the conductive heatdissipating wire wound around the outer circumference of the aerial line101, the heat of the aerial line is conducted to the conductive heatdissipating wire. The conductive heat dissipating wire is spirally woundaround the outer circumference of the aerial line 101 at a predeterminedpitch and projects from the surface, therefore promotes the convectionof the heat and, at the same time, effectively dissipates the heat inthe aerial line 101 by the radiator effect. Further, the current alsoflows through the conductive heat dissipating wire, so the amount of theincrease of the sectional area by this conductive heat dissipating wireincreases the transmission capacity of the entire aerial line. Namely,the aerial line 101 upon which the heat dissipator 102 comprising theconductive heat dissipating wire is laid is increased in itstransmission capacity as a whole.

As the method of winding the conductive heat dissipating wire of theheat dissipator 102 around the outer circumferential surface of theaerial line 101, if the conductive heat dissipating wire has arelatively short length, it is shaped into a spiral in advance andtherefore can be easily wound around the aerial line 101 manually. Ifthe conductive heat dissipating wire is made of a long wire material, itcan be continuously wound around the aerial line 101 by a self-propelledrobot, lashing machine, or the like. Accordingly, the conductive heatdissipating wire can be wound around aerial lines 101 by just stoppingthe transmission of power over all of the aerial lines and therefore canbe installed in a short time. Namely, it is sufficient to just wind aconductive heat dissipating wire around an already existing aerial line101, therefore it is not necessary to replace the already laid aerialline and consequently an increase of the transmission capacity of theaerial line can be realized in a short time economically.

As illustrated in FIGS. 12B and 12C, if two or more conductive heatdissipating wires of the aerial line 101 are wound in the longitudinaldirection of the aerial line 101, the overall surface area of theconductive heat dissipating wires of the heat dissipator 102 isincreased and the heat dissipation effect can be further raised.Further, the transmission capacity of the aerial line is increased.

The relationship DD/dd between the diameter (or radius) of the strandsof the outermost layer of the aerial line 101 (hereinafter, referred toas the outer layer strand diameter dd of the aerial line) and thediameter of the heat dissipating wires or the thickness DD of the powertransmission wire 101 in the radius direction, the relationship PP/ppbetween the twist pitch pp of the outermost strands of the aerial line101 and the winding pitch PP of the dissipating wires around the powertransmission wire 101, and the heat dissipation rate will be considered.

First, the heat dissipation rate will be explained. As explained also inthe description of the first embodiment, the factors determining thetemperature rise of the aerial line include the heat absorbed from thesun and thermal diffusion from the aerial line due to radiation of heat,but the characteristics change according to the material and the surfacestate of the aerial line. The factors are expressed by coefficients suchas an absorption rate and the heat dissipation rate, but usually the twoare not differentiated and are referred to overall as the heatdissipation rate. Below, the heat dissipation rate η will be used. Theheat dissipation rate changes by a large extent according to the surfacestate of the aerial line. The heat dissipation rate η is 0.08 to 0.16 ina new line comprised of steel-reinforced aluminum conductors (ACSR), butthe heat dissipation rate η is regarded as becoming about 0.9 on thewhole when the line becomes old and the surface becomes more aged and isblackened.

The heat is conducted from the high temperature locations. In heatdissipation, one method of this heat conduction, electromagnetic waves(infrared rays) are directly radiated from the heat source. These strikeanother object to become heat again. Accordingly, if the rod surface istreated to blacken it in advance from the initial state like theconductive heat dissipating wire in the heat dissipator 1 so as to raisethe heat dissipation rate, the rate of heat absorption from the linebecomes higher and the effect of suppressing the temperature rise of theline is raised as a result.

From the above consideration, in the present embodiment as well, thesurface heat dissipation rate η of the heat dissipating wireconstituting the heat dissipator 102 is desirably 0.7 or more. Bytreating the surface of the conductive heat dissipating wire to blackenit and raise the surface heat dissipation rate to 0.7 or more, the heatof the aerial line 101 is effectively absorbed and the heat dissipationof the aerial line 101 is promoted and therefore the temperature rise ofthe aerial line 101 can be suppressed. Further, in comparison with asurface heat dissipation rate of about 0.1 to 0.2 like the spiral rod ofthe related art, if the surface of the conductive heat dissipating wireof the heat dissipator 102 of the embodiment of the present invention istreated to blacken it to raise the surface heat dissipation rate to 0.7(4.5 to 3.0 converted to luminance) or more, there is a large effect ofsmoothly melting snow adhered to the surface of the aerial line.

The surface-blackening treatment of the conductive heat dissipating wireconstituting the heat dissipator 102 will be explained next. In thepresent embodiment as well, preferably aluminum or aluminum alloy isused for the conductive heat dissipating wire. As the method ofblackening the surface of the aluminum or the aluminum alloy, asexplained above, for example, other than sand blasting, boehmitetreatment, painting, etc., electric, chemical, and physical processescan be used. For example, in order to easily blacken the surface ofaluminum heat dissipating wire, silicic acid is effective. If calciumsulfate or zinc carbonate or zinc sulfate is added to a sodium silicatesolution, the surface of the conductive heat dissipating wire made ofaluminum can be discolored black in a certain concentration range. Ifthe surface of the aluminum wire material is roughened by applying sandblasting or the like before applying the blackening treatment to makethe surface hydrophilic, a black surface having a high heat dissipationrate is obtained and, at the same time, an improvement of the coronanoise characteristic can be achieve.

Next, the relationship between the winding pitch PP of the heatdissipator and the twist pitch pp of the outer layer strands of theaerial line and the relationship between the rod diameter DD of the heatdissipator and the outer layer strand diameter dd of the aerial linewill be explained.

The relationship DD/dd between the outer layer strand diameter dd of theaerial line 101 and the diameter of the heat dissipating wire or thethickness DD of the aerial line 101 in the radial direction and therelationship PP/pp between the winding twist pitch pp of the outer layerstrands of the aerial line 101 and the winding pitch PP of the heatdissipating wire around the aerial line 101 are desirably the following:

 0.8≦DD/dd≦2.0  (3)

0.8≦PP/pp≦5.0  (4)

The reason for the relations will be explained next.

a. If DD/dd≦0.8, the diameter or height of the conductive heatdissipating wire would become small, and therefore the self windingforce around the aerial line 101 would become small, so there would bean apprehension of unraveling due to vibration of the aerial line 101 orthe like. If DD/dd≧2.0, the rigidity of the conductive heat dissipatingwire would become too large, and, when the conductive heat dissipatingwire has a short length, not only would the end of the conductive heatdissipating wire scratch the aerial line 101 at the time of winding, butalso the corona noise level would be raised, so this would unsuitable inpractical use. Further, when the conductive heat dissipating wire ismade of a long wire material, the rigidity would become large, thereforethere would be the apprehension such that the winding would no longer beable to be carried out with automatic winding by a lashing machine orthe like. Further, if DD/dd≧2.0, the increase of the line tension andthe increase of the wind pressure resistance after the winding of theconductive heat dissipating wire around the aerial line 101 would occurand there would be the inconvenience that the tower etc. must bereinforced or there would be a large loss in view of economy.

b. If PP/pp≦0.8, the amount of winding per unit length of the conductiveheat dissipating wire would be increased. Due to the increase of theweight of the line and the increase of the wind pressure resistanceafter the winding, not only would there be an adverse influence exertedupon the strength of the tower, but also there would be disadvantages inview of the economy. Further, if PP/pp≧5.0, the winding member forobtaining the required heat dissipation effect would become small, andthe sufficient heat dissipation effect would no longer be able to beobtained. In addition, the effect of prevention of wind noise and theprevention of accumulation of snow would be reduced.

As explained above, when relation 3 stands for DD/dd, the installationwhen winding the heat dissipating wire around the aerial line 101becomes easy, the increase of the tension of the aerial line by thewinding and the increase of the wind pressure load can be suppressed,and a reduction of the wind noise can be achieved. Further, when therelation 4 is stands for PP/pp, the installation when winding the heatdissipating wire around the aerial line 101 is improved and a reductionof the wind noise and accumulation of snow can be achieved in relationto DD/dd.

Further preferably, the relations may be set as follows:

1.0≦DD/dd≦1.2  (5)

1.0≦PP/pp≦2.0  (6)

Next, various forms of the conductive heat dissipating wire constitutingthe heat dissipator 2 will be explained by referring to FIGS. 13A to13E.

The conductive heat dissipating wire 102 ₁ illustrated in FIG. 13A isone having a hollow circular cross-section having a diameter of DD andmost ordinarily used. The conductive heat dissipating wire 102 ₁ havinga circular cross-section is made of aluminum or aluminum alloy. Theproduction of such a conductive heat dissipating wire 102 ₁ is easy andalso the price is cheap, therefore if such a conductive heat dissipatingwire is used, it is economical. Further, it is easy to wind such aconductive heat dissipating wire 102 ₁ around the aerial line 101.

The conductive heat dissipating wire 102 ₂ illustrated in FIG. 13B is aconductive heat dissipating wire having a partially fan-like (segmentlike) cross-section. A conductive heat dissipating wire having such ashape is effective for improving the corona characteristic bysuppressing the height of projection from the surface of the aerial line101. If it is wound around a high voltage power transmission wire, thewind pressure resistance can be reduced. Further, if such a conductiveheat dissipating wire having a segment like cross-section is woundaround the power transmission wire 1, the contact area with the surfaceof the aerial line 101 is increased and the heat dissipation effect canbe raised. The segment like conductive heat dissipating wire 102 ₂ ismade of aluminum or aluminum alloy wire. The thickness DD thereof isequal to 4 to 5 mm in the case where for example the outer diameter ofthe aerial line 101 is about 38.4 mm. In the case where the aerial line101 is a thin aerial ground line having an outer diameter of 10.5 mm andcomprises seven twisted strands with diameters of the twisted strands ofthe outermost layer of 3.6 mm, DD is equal to about 2 mm.

Using the hollow circular conductive heat dissipating wire 102 ₃ havingthe diameter DD illustrated in FIG. 13C as the conductive heatdissipating wire of the heat dissipator 102 is effective when desiringto reduce the weight and keep down an increase in the line tension.Namely, if the hollow circular conductive heat dissipating wire 102 ₃ isused as the heat dissipator 102, the effect of the load upon the towersetc. can be greatly reduced. The hollow circular conductive heatdissipating wire 102 ₃ is comprised of aluminum or aluminum alloy wire.

Using the hollow oval conductive heat dissipating wire 102 ₄ illustratedin FIG. 13D as the conductive heat dissipating wire of the heatdissipator 102, in the same way as the hollow circular conductive heatdissipating wire 102 ₃ illustrated in FIG. 13C, is effective whendesiring to reduce the weight and keep down an increase in the linetension. The hollow oval conductive heat dissipating wire 102 ₄ iscomprised of aluminum or aluminum alloy wire.

The grooved conductive heat dissipating wire 102 ₅ provided with one ormore grooves on the outer circumference of the circular cross-sectionillustrated in FIG. 13E has the effect that only small drops of water R₁remain on the conductive heat dissipating wire due to the grooves G. Forexample, when the diameter of the conductive heat dissipating wire isrelatively large, if the circular conductive heat dissipating wire 102 ₁illustrated in FIG. 13A without the grooves is used, large drops of rainR₁ remain at the bottom of the conductive heat dissipating wire 102 ₁ atthe time of rain or the like, a corona is generated with a low potentialgradient (a value of an opposite sign from and an equal absolute valueto the field intensity), and the corona noise becomes large. However, inthe grooved conductive heat dissipating wire 102 ₅ illustrated in FIG.13E, the drops of rain concentrate along the grooves G, the water ismore easily shed, and only small drops of rain R₂ remain, therefore thecorona characteristic is improved. Further, by providing a plurality ofgrooves G on the surface of the conductive heat dissipating wire, evenif the wire has a cross-section which is not hollow, the surface areacontributing to the heat dissipation can be increased, therefore theheat dissipation characteristic becomes high. Further, the weight of theconductive heat dissipating wire can be reduced by the amount of theempty parts of the grooves. As mentioned above, by providing a pluralityof grooves along the surface of the conductive heat dissipating wire,the water can be more easily shed, the formation of large drops of wateris prevented, and the corona characteristic can be further improved. Asthe particular method of improving the corona characteristic, theconductive heat dissipating wire 102 ₅ provided with a plurality ofgrooves is wrapped around the power transmission wire 101 in closecontact with it so as to ease the surface potential gradient of theconductive heat dissipating wire equipped the plurality of grooves andfurther lower the corona noise level. At the same time, this also hasthe effect of reducting the wind noise and the amount of theaccumulation of snow. Particularly, in the conductive heat dissipatingwire of the present invention, as explained above, the surface heatdissipation rate was raised to 0.7 (4.4 to 3.0 converted to luminance)or more by treating the surface to blacken it, therefore there is agreater effect of smoothly melting the snow adhered to the surface ofthe power transmission wire 101 in comparison with one having a surfaceheat dissipation rate of about 0.1 to 0.2 like the spiral rod of therelated art.

SIXTH EMBODIMENT

FIG. 14 is a view of the outer appearance of a heat dissipator for apower transmission wire and a power transmission wire equipped with aheat dissipator of a sixth embodiment of the present invention.

In the fifth embodiment illustrated in FIG. 11, an example in which aheat dissipator 102 using a long conductive heat dissipating wire waswound around the aerial line 101 was illustrated, but in the exampleillustrated in FIG. 14, a heat dissipator 107 comprising rods 71 and 72having relatively short lengths, i.e., a length of L, and shaped in theform of open spirals in advance is continuously laid. In the heatdissipator for a power transmission wire or the power transmission wireequipped with a heat dissipator illustrated in FIG. 14, the anchor clamp4 and the jumper clamp 5 are connected, the aerial line 101 is extendedto the anchor clamp 104, and the conductive heat dissipating wires (orconductive heat dissipating rods) 107 ₁ and 107 ₂ having the length Lare wound around the outer circumference of the aerial line 101. Thejumper 106 is connected to the jumper clamp 105. The heat dissipator 107is constituted by a plurality of such conductive heat dissipating wires107 ₁ and 107 ₂.

The length L of the conductive heat dissipating wire 107 ₁ desirably is1 to 3 m since it is wound manually and this is a length that can beeasily handled.

As to the sectional shape of the aerial line 101 and the arrangement ofthe conductive heat dissipating wires 107 ₁ and 107 ₂ to be wound aroundthe aerial line 101, it is possible to use those illustrated in FIGS.12A to 12C. As to the sectional shape of the conductive heat dissipatingwires 107 ₁ and 107 ₂, it is possible to use the shapes of theconductive heat dissipating wires illustrated in FIGS. 13A to 13E. Thematerial of the conductive heat dissipating wires 107 ₁ and 107 ₂ ispreferably aluminum or aluminum alloy in the same way as the conductiveheat dissipating wires explained above. The relationship between thetwist pitch pp of the outer layer strands of the aerial line 101 and theouter layer strand diameter dd of the aerial line and the relationshipbetween the winding pitch PP of the conductive heat dissipating wire 107₁ constituting the heat dissipator 107 and the outer diameter or thethickness DD in the diametrical direction of the segment wire aresimilar to those of relations 3 to 6 explained in the fifth embodiment.

Accordingly, the sixth embodiment of the present invention illustratedin FIG. 14 exhibits a similar effect to that explained in the fifthembodiment except for the point that installation upon an already strungaerial line 101 is facilitated by using conductive heat dissipatingwires having short lengths.

SECOND EXPERIMENTAL EXAMPLE

FIG. 15 is a view of an experiment in which a constant current is passedthrough a part AA of the aerial line 101 upon which the above-mentionedsurface-blackened heat dissipator 102, 107 is laid and a part BB of theaerial line 101 on which the heat dissipator is not laid from atransformer Tr and the surface temperature of the aerial line at thepart AA and the surface temperature of the aerial line at the part BBare measured. An aerial line 101 having a length of 150 m was bent backat 75 m. The aerial line 101 at the section AA and the aerial line 101at the section BB were laid in parallel. Steel-reinforced aluminumconductors (ACSR) were used as the aerial line 101. The sectional areaof the ACSR was 410 mm², the thickness dd of the outer layer strands was4.5 mm, and the twisting pitch pp of the outer layer strands was 290 mm.The conductive heat dissipating wire 107 ₁ of the heat dissipator 107had a thickness (diameter) DD of 6 mm and was wound at a winding pitchPP=250 mm around the aerial line (ACSR) as illustrated in FIG. 14.Accordingly, DD/dd=1.25, and PP/pp=1.0. A current of 1500 A was passedfrom the transmission device Tr to the power transmission wire 1.Measurements were made under an environment of a wind speed of 0.8 m/s.

FIG. 16 is a graph of the results of the experiment illustrated in FIG.15. The abscissa indicates the length (m) of the aerial line, and theordinate indicates the surface temperature (° C.) of the aerial line.The curves AA1 to AA3 indicate the surface temperatures of the aerialline in the section AA with respect to the length direction, while thecurves BB1 to BB3 indicate the surface temperatures of the aerial linein the section BB with respect to the length direction. The curves AA1and BB1 show the result of measurement of the temperature risecharacteristic after the elapse of 21.5 minutes from the start of thesupply of power, the curves AA2 and BB2 show the result of measurementof the temperature rise characteristic after an elapse of 50.1 minutesfrom the start of the supply of power and where the highest temperaturehas not yet been reached, and the curves AA3 and BB3 show the result ofmeasurement of the temperature rise characteristic after the elapse of80 minutes from the start of the supply of power.

As illustrated in FIG. 15, the distance S₁=30 m and the distance S₂=120m are distances equal from the two ends of the aerial line 101. Whencomparing the curve AA3 and the curve BB3 at these positions, thesurface temperature of the aerial line around which the conductive heatdissipating wire is not wound was 140° C. as indicated by the curve BB3,while the surface temperature of the aerial line around which theconductive heat dissipating wire is wound was 115° C. as indicated bythe curve AA1. When comparing the two, a reduction of the surfacetemperature of 25 degrees was obtained by providing the heat dissipator107.

The temperature reduction effect of the heat dissipator 107 becomes moreconspicuous as the temperature becomes higher. For example, thetemperature difference between the curve AA1 and the curve BB1 at thedistance S₁=30 m and the distance S₂=120 m was 5° C., the temperaturedifference between the curve AA2 and the curve BB2 was 10° C., and thetemperature difference between the curve AA3 and the curve BB3 was 25°C.

As described above, by winding the heat dissipators 102 and 107 aroundthe power transmission wire 101, it is possible to promote the heatdissipation of the aerial line 101 and lower the temperature of theaerial line 101. The reduction of the temperature of the aerial linealso leads to a reduction of the increase of the sag of the aerial line.

The higher the temperature of the aerial line, the more remarkable thetemperature reduction effect by the winding of the heat dissipators 102and 107 around the aerial line.

By winding a plurality of conductive heat dissipating wires around theaerial line, the temperature reduction effect becomes more remarkable.

THIRD EXPERIMENTAL EXAMPLE

FIG. 17 is a graph of the corona noise characteristic at the time ofpouring water and at the time of a light rain for the case where heatdissipators are attached to power transmission wires and the case wherethey are not attached to power transmission wires.

Four aerial lines 101 comprised steel-reinforced aluminum conductors(ACSR) of 810 mm² sectional area (space between lines=500 mm square,d=4.8 mm, p=410 mm) were used. When winding conductive heat dissipatingwires around the aerial lines, two conductive heat dissipating wireswere attached to the four lines in close contact. The winding pitch P ofthe conductive heat dissipating wires of the heat dissipators 107 aroundthe aerial lines was set to a constant 350 mm, and the diameter D of theconductive heat dissipating wires was changed to three types, that is,φ5, φ6, and φ7 for the measurement. The ordinate of FIG. 17 indicatesthe corona hum level (dB(A)), while the abscissa indicates the maximumpotential gradient (kV/cm).

The “time of pouring water” means the time of rainfall of 30 mm/h, whilethe “time of light rain” means the time of a light rain equivalent to 3mm/h.

The characteristic in the case of light rain when conductive heatdissipating wires are not wound around the aerial line 101 is indicatedby a curve CV10 comprised of the broken line connecting the black dots,while the characteristic in the case of pouring water is indicated by acurve CV20 comprised of the broken line connecting the black dots. Thecharacteristics in the case of light rain when conductive heatdissipating wires having diameters D of φ5, φ6, and φ7 are wound aroundthe outer circumferential surfaces of the aerial lines 101 are indicatedby the curves CV11 to CV13, while the characteristics in the case ofpouring water are indicated by the curves CV21 to CV23.

Viewed as a whole, the corona hum is larger at the time of pouring waterthan at the time of light rain.

The maximum potential gradient of an ultra high pressure aerial line of500 kV is usually about 11 to 12 kV/cm, though depending on the mountingdesign, therefore when compared with this value, the corona humcharacteristic naturally is a better value in the case where heatdissipators are not attached to the aerial lines 101. The deteriorationof the characteristic due to the attachment of the heat dissipators tothe aerial lines 101 becomes worse as the diameter become thinner, butthe difference is about several dB(A) at most. The difference is 1.5 to3 dB(A) in comparison with the case where heat dissipators are notattached to the aerial lines 101 and therefore is a value not causingany problem. Namely, it was seen that the corona noise was not largelyincreased even if the heat dissipators of the present embodimentprojecting from the outer surface of the aerial lines were attached onthe aerial lines.

Note that, the term “mounting design” means, in the design of the towerholding the power transmission wires, the design of the vertical spaceand horizontal space between arms of the tower based on designspecifications in order to maintain the transmission voltage or thepredetermined insulation intervals in areas with strong winds, areaswith icing, etc.

FOURTH EXPERIMENTAL EXAMPLE

FIG. 18 is a graph of the results of measurement of the wind noise levelunder the conditions of aerial lines and heat dissipators the same asthose of FIG. 17.

Two aerial lines 101 comprised of steel-reinforced aluminum conductors(ACSR) of a sectional area of 810 mm² (space between lines=500 mmsquare, d=4.8 mm, p=410 mm) was used. Conductive heat dissipating wireswere attached to the conductors of the two aerial lines. The two lineswere placed in a wind tunnel with their centers positioned 1 m from theblowing port, then the wind noise level was measured at a wind speed of20 m/s.

The curve connecting the black dots shows the result of measurement ofthe wind noise in the case where the conductive heat dissipating wiresare not attached. The curve connecting the triangles shows the result ofmeasurement of the wind noise in the case where conductive heatdissipating wires of φ7 are wound around the power transmission wire,the curve connecting the diamonds shows the result of measurement of thewind noise in the case where conductive heat dissipating wires of φ6 arewound around the aerial lines, and the curve connecting squares showsthe result of measurement in the case where conductive heat dissipatingwires of φ5 are wound around the power transmission wires.

Note that, in the figure, BN indicates the “background noise” and isgiven for comparison.

When heat dissipators 102 are not attached to the aerial lines, anoutstanding frequency giving the maximum wind noise value of 62 dB(A)appears in the vicinity of 125 Hz. This becomes the cause of the windnoise. Particularly, this noise has a low frequency, and dull sound, sothe attenuation over a distance is small and the noise can be heard at afar place. Accordingly, this frequently causes complaints about noise.It was confirmed that if heat dissipators were attached, the outstandingfrequency disappeared, the noise level at the peak frequency was greatlyreduced to 13 to 16 dB(A), and the sound almost completely disappearedand that therefore the noise level could be suppressed to a sufficientlylow level that did not cause complaints about noise.

Note that, the term “outstanding frequeny” means the frequency givingthe maximum noise level and is expressed by f=S×v/D (Hz), where S is theStrohall number and is approximately equal to 0.185 to 2.1, V is thewind speed (m/s), and D is the outer diameter (m) of the aerial line.

Regarding the influence of the diameter of a heat dissipator upon thenoise level, a conductive heat dissipating wire of φ7 is excellent(curve connecting triangles), but there is a sufficient effect even by aconductive heat dissipating wire having a diameter less than this. Whenconsidering the installation, economy, the previous corona humcharacteristic, etc. together, even a conductive heat dissipating wirehaving a diameter of φ5 sufficiently satisfies the performancerequirements.

The heat dissipator of the present invention may not only be applied toalready strung aerial lines as shown in the embodiments, but also tonewly strung power transmission wires. In order to increase thecapacity, in the case of newly strung lines, it is possible toartificially age the surface in advance by sand blasting or boehmitetreatment or other electrical and chemical treatment methods to raisethe surface heat dissipation rate so as to obtain a surface heatdissipation rate comparable to that of a naturally aged aerial lineimmediately after laying it and therefore more effectively increase thecapacity.

While the above description was mainly made of the case where the heatdissipator of the present invention was applied to a single line (onepower transmission wire), the present invention can also be applied tothe case of multiple lines, for example, two, three, four, six, eight,10, and other lines in the same way as that explained above. In thiscase, spacers are attached to the multiple power transmission wires atintervals of 20 to 70 m. It is possible to stop winding the heatconducting heat dissipators in the vicinity of the clamps of the spacersor to modify the clamps so as to grip the heat dissipators from the toptogether. Such a means can be appropriately selected and executedaccording to the particular situation.

CAPABILITY OF UTILIZATION IN INDUSTRY

The heat dissipator for a power transmission wire of the presentinvention explained above can be utilized for the purpose of the heatdissipation of an aerial line and, as a result of this, can increase thetransmission capacity of an aerial power transmission wire.

Further, a power transmission wire equipped with a heat dissipatorprovided with a heat dissipator can be used for an aerial line and otherpower transmission wires.

What is claimed is:
 1. A heat dissipator for a power transmission wirecomprised of a conductive heat dissipation member having conductivityand having a surface heat dissipation rate of 0.7 or more spirally woundaround the outer circumferential surface of the power transmission wireat a predetermined winding pitch in close contact thereto.
 2. A heatdissipator for a power transmission wire as set forth in claim 1,wherein the conductive heat dissipation member is treated to blacken itssurface and delustered.
 3. A heat dissipator for a power transmissionwire as set forth in claim 1, wherein the surface of the conductive heatdissipation member is treated to make it hydrophilic.
 4. A heatdissipator for a power transmission wire as set forth in claim 1,wherein the conductive heat dissipation member has a surface which isartificially or naturally aged in advance.
 5. A heat dissipator for apower transmission wire as set forth in claim 1, wherein the conductiveheat dissipation member is produced by aluminum or an aluminum alloy. 6.A heat dissipator for a power transmission wire as set forth in claim 1,wherein the conductive heat dissipation member of the heat dissipatorfor a power transmission wire has a conductive, surface-blackened heatdissipating spiral rod having a surface heat dissipation rate of 0.7 ormore spirally formed in the longitudinal direction so that it can beattached on the outer circumferential surface of the power transmissionwire in close contact thereto and the spiral rod is spirally woundaround the outer circumferential surface of the power transmission wireat a predetermined winding pitch.
 7. A heat dissipator for a powertransmission wire as set forth in claim 6, wherein a winding pitch p ofthe surface-blackened heat dissipating spiral rod is set within thefollowing range with respect to the outer diameter D of the powertransmission wire: 10D≦p≦30D.
 8. A heat dissipator for a powertransmission wire as set forth in claim 6, wherein the surface-blackenedheat dissipating spiral rod is wound around the outer circumferentialsurface of a jumper at the tension support of the power transmissionwire.
 9. A heat dissipator for a power transmission wire as set forth inclaim 1, wherein a conductive heat dissipation member of the heatdissipator for a power transmission wire has a surface-blackenedconductive heat dissipation member which is flexible, electricallyconductive, and has a surface heat dissipation rate of 0.7 or more to beattached on the outer circumferential surface of the power transmissionwire in close contact thereto, and the conductive heat dissipationmember is spirally wound around the outer circumferential surface of thepower transmission wire at a predetermined winding pitch.
 10. A heatdissipator for a power transmission wire as set forth in claim 9,wherein when the strand diameter of the outermost layer of the powertransmission wire is dd, the outer diameter of the surface-blackenedconductive heat dissipation member or the thickness in the diameterdirection is DD, the pitch of the twist of the strand of the outer layerof the power transmission wire is pp, and the winding pitch of theconductive heat dissipation member around the outer circumferentialsurface of the power transmission wire is PP, the following relationsstand: 0.8≦DD/dd≦2.0, and 0.8≦PP/pp≦5.0.
 11. A heat dissipator for apower transmission wire as set forth in claim 9, wherein when the stranddiameter of the outermost layer of the power transmission wire is dd,the outer diameter of the surface-blackened conductive heat dissipationmember or the thickness of the diameter direction is DD, the pitch ofthe twist of the strand of the outer layer of the power transmissionwire is pp, and the winding pitch of the conductive heat dissipationmember around the outer circumferential surface of the powertransmission wire is PP, the following relations stand: 1.0≦DD/dd≦1.2,and 1.0≦PP/pp≦2.0.
 12. A heat dissipator for a power transmission wireas set forth in claim 9, wherein the cross-section of the conductiveheat dissipating member is circular.
 13. A heat dissipator for a powertransmission wire as set forth in claim 9, wherein the cross-section ofthe conductive heat dissipating member is a partially fan-like segment.14. A heat dissipator for a power transmission wire as set forth inclaim 9, wherein the cross-section of the conductive heat dissipatingmember is a hollow circle.
 15. A heat dissipator for a powertransmission wire as set forth in claim 9, wherein the cross-section ofthe conductive heat dissipating member is a hollow oval.
 16. A heatdissipator for a power transmission wire as set forth in claim 9,wherein a groove for suppressing the formation of drops of water isformed along the circumference of the conductive heat dissipating memberhaving a circular cross-section.
 17. A heat dissipator for a powertransmission wire as set forth in claim 9, wherein a winding pitch p ofthe surface-blackened heat dissipating spiral rod around the powertransmission wire is set to the following range with respect to theouter diameter D of the power transmission wire: 10D≦p≦30D.
 18. A heatdissipator for a power transmission wire as set forth in claim 9,wherein the surface-blackened heat dissipating spiral rod is woundaround the outer circumferential surface of the jumper at a tensionsupport of the power transmission wire.
 19. A heat dissipator for apower transmission wire comprised of a conductive heat dissipationmember having conductivity and having a surface heat dissipation rate of0.7 or more spirally wound around the outer circumferential surface ofthe power transmission wire at a predetermined winding pitch in closecontact thereto, wherein the conductive heat dissipation member is abraided heat conducting wire heat dissipating belt comprised of heatconducting metal strands braided in the form of a mesh belt.
 20. A heatdissipator for a power transmission wire as set forth in claim 19,wherein the braided heat conducting wire heat dissipating belt has awinding pitch giving a center angle θ of the winding width on thecircumference of the cross-section of the power transmission wire withthe center of the power transmission wire defined by the followingrelation: 15°≦θ≦180°.
 21. A heat dissipator for a power transmissionwire as set forth in claim 19, wherein a winding pitch p of the braidedheat conducting wire heat dissipating belt around the power transmissionwire is set within the following range with respect to an outer diameterD of the power transmission wire: 10D≦p≦30D.
 22. A heat dissipator for apower transmission wire as set forth in claim 6, wherein a spiral rod iswound on the braided heat conducting wire heat dissipating belt woundaround the outer circumferential surface of the power transmission wirein a reverse direction to the winding direction of the braided heatconducting wire heat dissipating belt to secure the winding of thebraided heat conducting wire heat dissipating belt.
 23. A heatdissipator for a power transmission wire as set forth in claim 19,wherein the heat conducting metal strand of the braided heat conductingwire heat dissipating belt is a wire made of aluminum or an aluminumalloy having a diameter of 0.3 mm to 3.0 mm.
 24. A heat dissipator for apower transmission wire as set forth in claim 19, wherein a plurality ofthe braided heat conducting wire heat dissipating belts are wound aroundthe outer circumferential surface of the power transmission wire in thesame direction or so as to cross.
 25. A heat dissipator for a powertransmission wire as set forth in claim 19, wherein an end of thebraided heat conducting wire heat dissipating belt wound around theouter circumferential surface of the power transmission wire is woundaround a front end of an anchor clamp to secure it.
 26. A heatdissipator for a power transmission wire as set forth in claim 19,wherein a braided heat conducting wire heat dissipating belt comprisedof a heat conducting metal strand braided in the form of a mesh belt iswound around the outer circumference of a jumper at a tension support ofthe power transmission wire, and the end of the braided belt member iswound around the front end of a jumper connection of the anchor clamp tosecure it.
 27. A power transmission wire having a heat conducting anddissipating means comprised of a conductive heat dissipation memberhaving conductivity and a surface heat dissipation rate of 0.7 or morespirally wound around the outer circumferential surface at apredetermined winding pitch in close contact thereto.
 28. A powertransmission wire as set forth in claim 27, wherein the conductive heatdissipation member is treated to blacken its surface and delustered. 29.A power transmission wire as set forth in claim 27, wherein the surfaceof the conductive heat dissipation member is treated to make ithydrophilic.
 30. A power transmission wire as set forth in claim 27,wherein the conductive heat dissipation member has a surface which isartificially or naturally aged in advance.
 31. A power transmission wireas set forth in claim 27, wherein the conductive heat dissipation memberis produced from aluminum or an aluminum alloy.
 32. A power transmissionwire as set forth in claim 27, wherein the power transmission wire isproduced from any of steel-reinforced aluminum conductors (ACSR),steel-reinforced ultra thermo-resistant aluminum alloy conductors(UTACSR), Invar-reinforced super or extra thermo-resistant aluminumalloy conductors (ZTACIR or XTACIR), and galvanized steel twisted wire.33. A power transmission wire having a heat conducting and dissipatingmeans comprised of a conductive heat dissipation member havingconductivity and a surface heat dissipation rate of 0.7 or more spirallywound around the outer circumferential surface at a predeterminedwinding pitch in close contact thereto, wherein the conductive heatdissipation member is a braided heat conducting wire heat dissipatingbelt comprised of a heat conducting metal strand braided in the form ofa mesh belt.
 34. A power transmission wire as set forth in claim 33,wherein a plurality of braided heat conducting wire heat dissipatingbelts are wound around the outer circumferential surface of the powertransmission wire in close contact thereto in the same direction or soas to cross.
 35. A power transmission wire as set forth in claim 27,wherein the conductive heat dissipation member is a conductive,surface-blackened heat dissipating spiral rod having a surface heatdissipation rate of 0.7 or more formed spirally in the longitudinaldirection so that it can be attached to the outer circumferentialsurface of the power transmission wire in close contact thereto.
 36. Apower transmission wire as set forth in claims 27, wherein theconductive heat dissipation member is a surface-blackened conductiveheat dissipation member which is flexible, electrically conductive, andhas a surface heat dissipation rate of 0.7 or more to be attached on theouter circumferential surface of the power transmission wire in closecontact thereto.
 37. A method of attaching a heat dissipator on a powertransmission wire comprising spirally winding a heat dissipation memberhaving conductivity and a surface heat dissipation rate of 0.7 or morearound the outer circumferential surface of an aerial line in closecontact thereto at a predetermined winding pitch.
 38. A method ofattaching a heat dissipator as set forth in claim 37, wherein theattachment work is carried out while transmitting power through thepower transmission wire.
 39. A method of attaching a heat dissipator asset forth in claim 37, wherein the conductive heat dissipation member isproduced from aluminum or an aluminum alloy.
 40. A method of attaching aheat dissipator as set forth in claim 37, wherein the conductive heatdissipation member is a conductive, surface-blackened heat dissipatingspiral rod having a surface heat dissipation rate of 0.7 or morespirally formed in the longitudinal direction so that it can be attachedto the outer circumferential surface of the power transmission wire inclose contact thereto.
 41. A method of attaching a heat dissipator asset forth in claim 40, wherein a winding pitch p of thesurface-blackened heat dissipating spiral rod around the powertransmission wire is set to the following range with respect to theouter diameter D of the power transmission wire: 10D≦p≦30D.
 42. A methodof attaching a heat dissipator as set forth in claim 37, wherein theconductive heat dissipation member is a surface-blackened conductiveheat dissipation member which is flexible, electrically conductive, andhas a surface heat dissipation rate of 0.7 or more to be attached at theouter circumferential surface of the power transmission wire in closecontact thereto.
 43. A method of attaching a heat dissipator as setforth in claim 42, wherein when the strand diameter of the outermostlayer of the power transmission wire is dd, the outer diameter of thesurface-blackened conductive heat dissipation member or the thickness ofthe diameter direction is DD, the pitch of the twist of the strand ofthe outer layer of the power transmission wire is pp, and the windingpitch of the conductive heat dissipation member around the outercircumferential surface of the power transmission wire is PP, thefollowing relations stand: 0.8≦DD/dd≦2.0, and 0.8≦PP/pp≦5.0.
 44. Amethod of attaching a heat dissipator as set forth in claim 42, whereinwhen the strand diameter of the outermost layer of the powertransmission wire is dd, the outer diameter of the surface-blackenedconductive heat dissipation member or the thickness of the diameterdirection is DD, the pitch of the twist of the strand of the outer layerof the power transmission wire is pp, and the winding pitch of theconductive heat dissipation member around the outer circumferentialsurface of the power transmission wire is PP, the following relationsstand: 1.0≦DD/dd≦1.2, and 1.0≦PP/pp≦2.0.
 45. A method of attaching aheat dissipator on a power transmission wire comprising spirally windinga heat dissipation member having conductivity and a surface heatdissipation rate of 0.7 or more around the outer circumferential surfaceof an aerial line in close contact thereto at a predetermined windingpitch, wherein the conductive heat dissipation member is a braided heatconducting wire heat dissipating belt comprised of a heat conductingmetal strand braided in the form of a mesh belt.
 46. A method ofattaching a heat dissipator as set forth in claim 45, wherein thebraided heat conducting wire heat dissipating belt has a winding pitchgiving a center angle θ of the winding width on the circumference of thecross-section of the power transmission wire with the center of thepower transmission wire defined by the following relation: 15°≦θ≦180°.47. A method of attaching a heat dissipator as set forth in claim 45,wherein a winding pitch p of the braided heat conducting wire heatdissipating belt around the power transmission wire is set within thefollowing range with respect to an outer diameter D of the powertransmission wire: 10D≦p≦30D.
 48. A method of attaching a heatdissipator as set forth in claim 45, wherein a plurality of the braidedheat conducting wire heat dissipating belts are wound around the outercircumferential surface of the power transmission wire in the samedirection or so as to cross.